US2516325A - Two-cycle type slide-valve internalcombustion engine - Google Patents

Description

July 25, 195o Filed Feb. 6, 1947 w. KAsTEN 2,516,325

Z-.CYCLE TYPE SLIDE VALVE INTERNAL-COMBUSTION ENGINE 2 Sheets-Sheet l,

INLET WIM/5aan fvfr VALVE w. KAsTEN 2,516,325

z-cYcLE TYPE SLIDE vALvE INTERNAL-COMBUSTION ENGINE July 25, 1950 2 Sheets-Sheet 2 Filed Feb. 6, 1947 I INVENTOR. www@ B Patented July 25, 1950 TWO-CYCLE TYPE SLIDE-VALVE INTERNAL- COMBUSTION ENGINE Walter Kasten, Franklin, Mich., assignor to Skinner Motors, Inc., Detroit, Mich., a corporation of Delaware Application February 6, 1947, Serial No. 726,807

7 claims. l

Heretofore 2cycle internal-combustion engines have been designed and built with one ported, single, reciprocatory sleeve or slide-valve controlling the exhaust-port which was located at the outer end of the piston travel, the companion intake-port being positioned at the other end of the combustion-chamber and opened and closed by the traveling piston, as disclosed, for example,

in United States Patent No. 2,194,252, A. A. Woodward, Two-Cycle Internal-Combustion Engine Valve Mechanism, granted March 19, 1940, and owned by Skinner Motors, Inc., the assignee of this present application and the patent to be granted thereon.

Occasionally I had considered the desirability or possibility of materially modifying this port arrangement, but in all cases only, one single sleeve or slide valve was used.

The idea suddenly and unexpectedly presented itself to me that quite a number of distinct advantages and improvements could be derived or obtained by using two slide-valves to control the admission and exhaust of the combustible medium in a 2-cycle engine.

This structural and functional feature has been found to be of particular benefit and advantage in a 2-cycle internal-combustion engine of relatively large bore stroke ratio, since its use makes.

it possible to operate an engine at more revolutions per minute and, therefore, to obtain greater power for a given size engine.

In order that those acquainted with or skilled in this art may fully understand and appreciate the structural and functional advantages accruing from the employment of the current invention, a present, preferred embodiment thereof in physical form has been illustrated in detail in the accompanying drawings, to which reference should be had, and which are completely described hereinafter.

In these drawings:

,Figure 1 is an external plan view of a 2-cycle two-cylinder horizontal engine incorporating the present invention with certain internal parts shown in dotted lines;

Figure 2 is a diagram of the timing operation of the several occurrences taking place in one of such cylinders; Y

Figure 3 is a vertical section on line 3-3 of Figure 4 through one of the engine-cylinders and a portion only of the second or companion one; and Figure 4 is an elevation of the right-hand end of the engine shown in Figure 1.

Referring to these drawings, it will be noted that each of the opposite, main-cylinders Il, I| is water-cooled or may be otherwise maintained at a suitable temperature, each such cylinder housing a shorter, smaller cylinder I2 mounted on or bearing against a suitably supported stationary ring I3 in, the engine crank-case.

Bearing against the other or outer end of such part |2 is a resilient ported ring III with its two ports, air-inlet I 5 and exhaust-outlet |6,.in register with the cylinder admission and exhaust ports I I and I8 respectively, such member I4 being held in the specified relation and position by another ring |9 in register therewith and pressed against it by a circular leaf-spring 2| mounted in the cylinder-head'22 of the engine, a round, resilient, pressure-sealing reed 23, also mounted in the cylinder-head, bearing against the inner surface of nart I9.

Slidable lengthwise between the two cylinders and l2 is a semi-circular air-inlet or admission valve 24` having a port 25 cooperating with the aligned stationary ports Il, I5, such valve being reciprocated by a rock-arm 26 connected therewith at 2l and hinged at 28 to a link 29 reciprocated by a cam or eccentric 3| on a. shaft 32 rotated by the main crank-shaft 33 of the engine through any suitable gearing or drive mechanism, not illustrated, such, for example, as shown in Figure 1 of said United States Patent No, 2,194,252 mentioned above.

In this particular arrangement the slidevalves are operated at one-half crank-shaft speed.

Inasmuch as the engine illustrated is a twocylinder, 2-cyc1e one the link 29 is made of double length and operates one of the valves of the second cylinder of the structure.

Also, between the outer and inner cylinders II and I2 is a similar, semi-circular exhaust-valve 34 having a discharge port 35 coacting with the registered, stationary exhaust-ports I6, I B, such valve 34 being reciprocated by mechanism |26, |21, |28, |29, |3| and |32 like the corresponding cooperating elements which actuate the inletvalve 24.

Each cylinder-head 22 of the engine has a fuelinjection nozzle 36 of known type through which the fuel is forced under pressure into the central portion of the cylinder intermittently in the usual manner but at a slightly inclined direction, the cylinder-head also having the usual sparkplug 30.

This novel cylinder-head, instead of having a flat inner surface, is provided with a suitable airdeflector 31 inwardly away from, but in front of, the inlet-port I5, such baille, deviator or swerver having an inwardly curved surface 38 facing the inlet-ports, such surface being also curved around the axis of the cylinder for at least the full length of port I5, as indicated in Figure 3.

As the cylinder-ports are located at the outer end portion of and on the opposite sides of the cylinder, and as there is an overlap or period during which both the inlet and exhaust valves are open, the ow of the gases is in material measure across the cylinder instead of along the 3 cylinder axis as in the case of previous R-cycle engines.

In order to lengthen the path of travel of the gas to scavenge some of the exhaust gases near the piston end of the combustion-chamber, the cylinder-head is provided with the deiiector referred to near or adjacent to the air-inlet port.

As will be observed from a consideration of Figure 3, the location of the ports are such that the piston-rings of the piston never quite reach them, suiiicient space being provided for the accommodation of the deilector 31 when the piston is at its outer extreme limit.

This described novel and improved construction affords the following distinct advantages over the conventional 2-cyc1e engines.

l. As there are two separate valves for each cylinder, one inlet and one exhaust, the period of and duration of each valve opening can be controlled separately and independently of the other;

2. Both valves can be operated at either onehalf crank-shaft speed or at crank-shaft speed;

3. The inlet-valve can be actuated at crankshaft speed and the exhaust-valve at one-half crank-shaft speed;

4. The exhaust-valve can function at crankshaft speed and the inlet-valve at one-half crank-shaft speed;

5. The air-deiiector is located in the fixed end of the cylinder bore, that is, on the cylinder-head and not on the reciprocatory piston which is the case in practically all 2-cycle engines, the location of such baiiie on the piston not being as beneficial since the piston moves and the position of the baille, therefore, relative to the port changes with this piston;

6. 'I'he deflector located on the cylinder-head makes for a cooler operating machine as the piston-head can be made 'flat with the least possible surface for the absorption of the heat in the combastion-chamber;

7. The location of the deflector on the cylinderhead makes it possible to provide better cooling for the deector;

8. As the exhaust-port is located on the outer end of the combustion-chamber away from the crank-shaft center, the piston operates at much lower temperature and the life of the pistonrings is considerably extended;

9. Since the piston-rings do not override either the exhaust-port or the inlet-port, as in the case of some 2-cycle engines, the life of these rings is furthermore prolonged and the oil losses through the ports are considerably reduced;

10. The piston and cylinder lubrication is improved because the oil for the lubricating film does not have to pass by any ports;

1l. Due to the fact that the valve timing is controlled independently of the piston any valve timing diagram or arrangement most suitable for the engine can be selected and employed.

In Vthe present case, the timing arrangement is shown in Figure 2, the circle representing the 360 degrees of crankshaft angle revolution, the top zero corresponding to the top dead-center of the piston where the explosion takes place, the ignition occurring approximately to 20 degrees before such top dead-center.

It will be noted that the adjustment in this particular structure has been so set that the exhaust-valve opens about 90 degrees after top dead-center and closes about 30 degrees after bottom dead-center has been passed.

4 The fuel-injection takes place approximately during the last two-thirds of the time during which the inlet-valve is open.

Those acquainted with this art will readily understand that this invention is not necessarily limited and restricted to the precise and exact details referred to, and that ordinary modifications may be availedof without departure from the heart and essence of the invention and without the loss or sacrifice of any of its material benefits and advantages.

I claim:

l. In the known type of 2-cycle internal-combustion engine having inner and outer spaced apart concentric cylinders, a cylinder-head closing the outer end of the outer cylinder, a crankshaft operating piston reciprocatory in said inner cylinder, and fuel injection and ignition means, the combination of novel features,that said engine has an air-inlet port and an exhaust-port in substantial register with one another through its opposite sides at the outer end portion of the combustion-chamber, a pair of independent slidevalves between said cylinders controlling the opening and closing of said engine-ports, means to reciprocate said valves, and a deiiector on said cylinder-head in front of said air-inlet port to direct entering air longitudinally of the combustion-chamber away from said cylinder-head whereby to assist in scavenging said chamber of exhaust-gases.

2. The combination of novel features in a 2- cycle internal-combustion engine set forth in claim 1, including in said combination the additional feature that the travel of said piston outwardly ceases before the piston-rings reach either of the engine-ports.

3. The combination of novel features set forth in claim l, including also the additional feature that said two valves are reciprocated at different speeds.

4. The combination of novel features set forth in claim 1, including also the additional feature that at least one of the two valves is reciprocated at one-half engine crankshaft speed.

5. The combination of novel features set forth in claim l, including also the feature that one of said valves is reciprocated at the same speed as the piston reciprocates, and that the other valve reciprocates at one-half that speed 6. The combination of novel features set forth in claim 1, including also the additional feature that the surface of said reflector on the cylinderhead facing said engine air inlet port is curved longitudinally of the engine cylinder.

7. 'Ihe combination of novel features set forth in claim l, including also the additional feature that said engine cylinder is equipped with an operating spark-plug to fire the explosive mixture in the cylinder.

WALTER KASTEN.

REFERENCES CITED The following references are of record in the ille of this patent:

UNITED STATES PATENTS Number Name Date 359,920 Cornell Mar. 22, 1887 1,638,288 Burtnett Aug. 9, 1927 `1,677,305 Sperry July 17, 1928 1,925,285 Smith .l Sept. 5, 1933 Certificate of Correction Patent No. 2,516,325 July 25, 1950 WALTER KASTEN It is hereby certified that error appears inthe printed specification of the above numbered patent requiring correction es follows:

Column 4; line 53, for the Word reflector read dejlector;

and that the said Letters Patent should be read as corrected above, so that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 7th day of November, A. D. 1950.

THOMAS F. MURPHY,

Assistant Oommzssz'oner of Patents.

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